Photographic printer and filter for use therewith



F 26, 1950 F. G. WIL DE 2,535,770 k PHOTOGRAPHIC PRINTER AND FILTER FOR USE THEREWITH Filed Feb. 21, 1948 Patented Dec. 26, i950 PHOTOGRAPHIC PRINTER AND FILTER FOR USE THEREWITH.

Frederick G. Wilde, Rochester; N;Y.,.assignor'to:

Paragon. Revolute Corporation,

Rochester,

NLY anorporation of New'Yorks ApplicatioirFebruary 21, 1948;" Serial No; 10,033

This inv'ention relates'to a' reproducin'g'apparatus utilizing light and moreparticularly to a filter for-use therein.

f In the making of reproductions from photog-raphic films, tracings, or the like; it is necessary in'the'casesof certain types ofphotosensitive sheets or papersto be printed, to use a light source of aparticular characteristic for example; in the range-between 5209- and 5700angstroms: Since various papers "require-light of -different character, different light filtersareutilized. to give tlie required light for any given type-of paper; These filters; dueto their necessarily curved arrangement in the printer, are currently made of a colored sheet of cellulose acetate. However, the colored cellulose acetate is subjected to such heat while it is in use, that it deteriorates rapidly and must therefore be frequently replaced.

The main feature of the present invention relates to the production of a light filter which obviates the need of using expendable cellulose acetate sheets.

Another feature of the invention relates to a glass filter adapted to be interposed between the light source and the sheet material to be printed, said filter having a chamber adapted to contain a transparent liquid such that it will obstruct the passage therethrough of undesired rays of light.

A further feature of the invention relates to a light filter through which a liquid can be circulated to filter out undesired light rays and to dissipate undesired heat.

Other features and advantages will appear from the detailed description and claims when taken with the drawings in which:

Fig. 1 is a diagrammatic showing of a photographic printer in which the present filter can be used;

Fig. 2 is a side view of the filter unit with a light source therein, the filter unit being so arranged that a cooling and light filtering medium can be circulated therethrough;

Fig. 3 is a longitudinal section through the filter unit of Fig. 2; and

Fig. 4 is a partial section of the filter unit taken on the line 4-i of Fig. 2, particularly showing the mounting of a quartz lamp and the light filter of the present invention.

Referring especially to Fig. 1, there is shown a printer of the type more fully disclosed in Patent 2,093,785 granted September 21, 1937. This printer comprises a table 5 along which a sheet of film or tracing to be reproduced, together with a photosensitive sheet in superimposed relation therewith, are advanced manually into suitable feed belt Tfu-rther travels-through a circuitous path whereby-it embraces the major portion of the" periphery 'of a rotatable transparent cylinder 8 of heat-resistantmaterialsuch as Pyrex glass or the'like. Theends'ofthe cylinder are supported for rotation" in' the printer in the well-known:

manner. It will be understood that the belts- 6 and grip the superimposed sheets -to advance them tothe point wherethey are-'engagedby the rotating cylinder 8 and the belt 7. The belt I advances and smoothly holds the superimposed sheets on the periphery of the cylinder for a printing period determined by the rate of travel of the belt. Within the cylinder there is fixedly mounted a light source it and an enclosing shield therefor. The light source can be a conventional quartz lamp while the shield comprises a transparent cylinder I l of heat resistant Pyrex glass or the like. The cylinder is preferably open at each end with its openings closed by the end caps I2. The construction of the shield and the mounting of the quartz lamp therein can be similar to that disclosed in the patent of Raymond R. Davis No. 2,457,353, granted December 28, 1948, and assigned to the same assignee as the present application.

In accordance with the present invention the cylinder H is made with spaced side walls Ha and Nb sealed together at their ends to provide a cylindrical chamber I d. This chamber encirces the light source l0 and is coextensive therewith. The cylinder is provided at each end thereof with connect on nipples l5 communicating with the chamber. The chamber [4 is filled with a suitable filtering medium l6 which may be clear or colored water as well as a clear or colored high temperature organic liquid such as Prestone. Where it is not necessary to dissipate heat, the connection nipples Hi can be corked as shown at !8 (Fig. 3). However, the liquid I 6 can be circulated as shown in Fig. 2 when heat must be withdrawn from the shield. In this form of the invention, a circulating system is connected to the respective hippies l5. Th s system comprises the tank 20, the pump 2| and the pipes 22 and 23.

What I claim is:

1. In combination with a printer for photosensitive sheets having a rotatable transparent contact cylinder, an elongated light source mounted within the cylinder to extend lengthwise thereof, movable belt-like means engaging the outer surface of said cylinder whereby said sheets are brought into contact with said surface to be printed by light transmitted from the source through the cylinder, a stationary transparent light filter open at its ends and enclosing said light source, said filter including an annular chamber interposed between said light source and said cylinder, and a light filtering fluid contained in said chamber through which photographic light is transmitted in the direction of said cylinder.

2. In combination with a printer for photosensitive sheets having a rotatable transparent contact cylinder, an elongated light source mounted within the cylinder to extend lengthwise thereof, movable belt-like means engaging the outer surface of said cylinder whereby said sheets are brought into contact with said surface to be printed by light transmitted from the source through the contact cylinder, a cylindrical stationary transparent light filter open at its ends and enclosing said light source, said filter including an annular chamber interposed between said light source and said contact cylinder, and a light filtering fluid contained in said chamber through which photographic light is transmitted in the direction of said contact cylinder.

3. In combination with a printer for photosensitive sheets having a rotatable transparent contact cylinder, an elongated light source mounted within the cylinder to extend lengthwise thereof, movable belt-like means engaging the outer surface of said cylinder whereby said sheets are brought into contact with said surface to be printed by light transmitted from the source through the contact cylinder, a cylindrical transparent light filter open at its ends and enclosing said light source, said filter including an annular chamber interposed between said light source and said contact cylinder, a source of light filtering fluid, means for recirculating the filtering fluid through said chamber whereby filtered photographic light is transmitted in the direction of said contact cylinder.

FREDERICK G. WILDE.

REFERENCES CITED I'he following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 907,598 Hewitt Dec. 22, 1908 1,895,887 Lorenz Jan. 31, 1933 1,966,547 Goode July 17, 1934 1,969,655 Mailey Aug. 7, 1934 2,041,478 Nederle May 19, 1936 2,063,296 Braune Dec. 8, 1936 2,093,785 Sullivan Sept. 21, 193'? 2,270,578 Campbell Jan. 20, 1942 2,297,587 Streich Sept. 29, 1942 2,308,130 Von Meister et al. Jan. 12, 1943 2,311,849 MacDonald Feb. 23, 1943 2,339,906 Barnes 1 Jan. 25, 1944 2,346,988 Noel Apr. 18, 1944 Boerstler July 31, 1945 

